gold cant decay from devision?

No gold was removed from being a decay possibility a long time ago.

i was plat for a while , then stopped playing ranked / league for a bit , it decayed to G1 , and iv been there for months ... >.> ranked just got boring to me

Your MMR is too high, keep losing games and you will drop. If your MMR drops to a silver level then ya you'll drop, I'm literally in gold getting placed with diamonds so I will never decay.

Gold cannot decay.

Only Plat V and higher decay.

Gold doesn't decay, so if you made it to gold and don't play for the rest of the season, you'll get gold rewards for whatever division you're in.

Of course placements next season take into account your mmr this season (and is soft-reset towards silver 4ish), so continuing to play and hopefully pull your mmr up will make getting gold next season easier (not to mention more practice so you get better, and slightly shinier borders this season depending on how you do).